diff --git a/httpd-core.scm b/httpd-core.scm
index 1c72fb1..4ca6654 100644
--- a/httpd-core.scm
+++ b/httpd-core.scm
@@ -130,8 +130,11 @@
 		; Files conform to CLF are expected to print the original line.
 		(or http-code "-")
 		(or filesize "-")
-		(or referer "")
-		(or user-agent "")))
+		(if (string? referer) (string-trim referer char-set:whitespace) "")
+		(if (string? user-agent) 
+		    (string-trim user-agent char-set:whitespace) 
+		    "")))
+
 
 ;;; (httpd options)
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;